Biochemical and histological changes during in vitro rooting of microcuttings of Bacopa monnieri (L.) Wettst
2018
Goel, Aanchal | Kaur, Amanpreet | Anil Kumar,
The present study was conducted to investigate the biochemical changes vis-à-vis histological changes during adventitious rooting of microcuttings of Bacopa monnieri (L.) Wettst. The rooting in these microcuttings was induced on basal MS medium and medium supplemented with different concentrations of indole-3-acetic acid and indole-3-butyric acid (IBA). Presence of lower auxin concentration (1.0 µM) in the medium enhanced rooting and significantly improved number of roots per shoot but maximum root length was observed on basal MS medium. Histological studies were conducted to identify different phases of rooting in these microcuttings. The root meristemoids with distinct polarity become visible after 3 days and mark the beginning of in vitro root initiation phase. It was followed by primordia elongation, root emergence and visible rooting on the 5th day of culture on medium supplemented with auxins. Biochemical studies were also conducted from basal portions of microcuttings cultured on MS medium supplemented with 1.0 µM IBA and control (basal MS medium) from 0 to 7 days. Total carbohydrate content was lower during initial periods (up to day 1) and was found to increase during root initiation and primordia development, which reflects high energy demands for active cell divisions. A significantly higher level of phenols was recorded in microcuttings on medium supplemented with IBA. Polyphenol oxidase, peroxidase (POX), ascorbate peroxidase activities were also found to vary during different phases of rhizogenesis. Early phases were also marked with the lower activities of POX and IAAO. This study revealed significant role of enzymes, sugars and phenols during different phases of rooting.
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